Actuators are used in myriad devices and systems. For example, many vehicles including, for example, aircraft, spacecraft, watercraft, and numerous other terrestrial and non-terrestrial vehicles, include one or more actuators to effect the movement of various control surfaces or components. Many different types of actuator configurations presently exist. One particular type of actuator is a linear electromechanical actuator (EMA). A typical linear EMA includes a power drive unit, an actuation member, and a translation member. The power drive unit, such as a motor, is configured to supply a drive torque to the actuation member, which in turn causes the translation member to translate.
One particular type of linear EMA is a ball screw actuator. This type of actuator includes a ball screw and a ball nut. The ball nut is mounted on, and is configured to rotate relative to, the ball screw. In some configurations, the ball screw is the actuation member, and the ball nut is the translation member. With these configurations, the power drive unit drives the ball screw, which causes the ball nut to translate. In other configurations, the ball nut is the actuation member, and the ball screw is the translation member. With these configurations, the power drive unit drives the ball nut, which causes the ball screw to translate. With either of these configurations, when the power drive unit is an electric motor, a relationship of motor current and force can be desirable for calibration purposes. Unfortunately, presently known actuators do not readily allow this relationship to be determined when a positive position device is not present.
Hence, there is a need for an actuator that readily allows the relationship of motor current and force to be readily determined when a positive position device is not present. The present invention addresses at least this need.